It is known in the art to provide means for adjusting the platen to accomodate different paper thicknesses. U.S. Pat. No. 4,365,900 is an example of such a platen adjusting device wherein adjustment is by an operator-controlled lever. Such prior art devices are relatively expensive requiring, for example, a roll carrier mounted for movement relative to the machine frame and adjustable by means of a hand controlled lever which acts upon eccentrics. The guiding means and the eccentrics must be so precise that the resultant adjustment of the platen is parallel to its basic position. This requires high costs for parts and assembly, and the parts must be produced with close tolerances. It is also of disadvantage in the known adjusting devices that the operator of the typewriter or printer often forgets to make the appropriate platen adjustment for proper passage of the paper so that the quality of the typed material is not always the best.
In accordance with the invention a paper guide trough is so mounted relative to a platen supported on an elastic bearing such that paper insertion causes the elastic bearing to accomodate movement of the platen.
It is an object of the invention to provide a platen adjusting device of simple design with a minimum of special parts.
It is another object of the invention to provide a platen adjusting mechanism in which the platen automatically moves to accomodate the thickness of an inserted paper pack.